Is an Idle Speed of 0.7 Normal?

[LaKyle]

An idle speed of 0.7 is normal, as the idle speed of a car varies between cold and warm engine states. More cylinders result in lower idle speeds: The idle speed of a car engine is primarily related to the stability of crankshaft rotation. The more cylinders there are, the better the force balance during crankshaft rotation, leading to smoother operation. Typically, a 12-cylinder engine has the lowest idle speed of only 500 RPM, an 8-cylinder engine's idle speed is around 600 RPM, a 6-cylinder engine's idle speed is approximately 600 RPM, and a 4-cylinder engine's minimum idle speed is 750 RPM. However, a 4-cylinder horizontally opposed engine eliminates the need for balance shafts and counterweights due to its horizontally opposed cylinders, allowing it to achieve a minimum idle speed of 650 RPM despite having only four cylinders. Larger displacement leads to lower idle speeds: Generally, the larger the engine displacement, the lower the idle speed. More cylinders naturally result in larger displacement, and with multiple cylinders working simultaneously, the stability is inherently better, allowing for lower permissible RPMs.

[LeHailey]

As a car owner, my vehicle's idle speed usually runs between 700-800 rpm. 0.7 thousand revolutions should be considered within the normal range. Many new cars are factory-set around 700 rpm for fuel efficiency and stability. However, it depends on the specific model. My compact car's idle speed increases slightly to about 750 rpm when the AC is on, and stays at exactly 700 rpm without AC. During cold starts, the rpm might initially surge to over 1000 before gradually dropping to 700 as the engine warms up. Once my car's idle speed dropped below 600 rpm, causing severe vibration - later diagnosed as carbon buildup in the throttle body, which was resolved after cleaning. I recommend observing whether the idle speed needle remains stable without fluctuation. If it's consistently unstable or fluctuates abnormally, there might be issues with components like the air filter or sensors. Normal idle speeds typically range between 600-1000 rpm, so 700 rpm is perfectly fine. But if accompanied by vibrations or increased fuel consumption, these symptoms shouldn't be ignored.

[MaximusRose]

I think an idle speed of 0.7 thousand revolutions (700 rpm) is considered normal for most cars, such as economy gasoline vehicles or daily commuter cars. The Engine Control Unit (ECU) adjusts the idle speed based on sensor data to maintain high combustion efficiency, and 0.7 is quite ideal. But don't just focus on the number—there are many influencing factors: for example, turning on the air conditioning or using more electrical devices can slightly increase the idle speed; it might also be higher when starting in cold weather but drop after the engine warms up. There are slight differences in idle speed settings between manual and automatic transmission cars. Once, my friend's car suddenly dropped to just over 500 rpm, causing the car to jerk, and the issue turned out to be a faulty oxygen sensor. My advice is that if the engine sounds smooth, there's likely no major issue. But if the idle speed becomes unstable or rises, you should check the ignition system or throttle. Maintaining 700 rpm long-term is quite good and can even save a bit on fuel costs.

[StRosalie]

An idle speed of 0.7 thousand RPM is normal, as many new cars are set to this value. The checking method is simple: after starting the car, observe the dashboard to see if the needle stabilizes at 700 RPM without fluctuation. However, if the idle speed exceeds 1000 or drops below 600, you should be alert. Common issues such as a clogged air filter, low battery voltage, or ignition coil failure can cause idle speed variations. It is recommended to clean carbon deposits during regular maintenance to maintain stable idle speed. Safety first, as too low idle speed may cause the engine to stall, especially in traffic jams. Pay attention to engine sounds and fuel consumption to prevent minor issues.

[StJuliet]

When I first started driving, I was also concerned about idle speed issues. Later, I read in the manual that 0.7 thousand RPM is the standard value, which put my mind at ease. New cars are designed to idle at 700 RPM to balance fuel consumption and emissions, so there's no need to worry about minor parameter fluctuations. However, you should verify it during actual driving: for example, check if the idle speed remains stable during traffic jams. If it drops, it might indicate an issue with the intake system. I had a similar experience where the idle speed drifted, and it turned out to be aging spark plugs—replacing them restored it to 700 RPM. My advice to beginners is not to worry too much; drive more to understand your car's behavior. If the car is old or the idle speed frequently fluctuates, get it checked early to avoid costly major repairs.

[SanAva]

An idle speed of 700 RPM is normal in most cases, as this is a common setting for modern gasoline engines to control emissions and fuel efficiency. However, consider the scenario: in cold weather, the idle speed may be slightly higher, and rising to around 750 RPM with the AC on is acceptable. If the idle speed suddenly drops below 600 RPM or surges above 800 RPM, it could indicate engine issues such as clogged fuel lines or faulty sensors. Long-term observation is beneficial, as maintaining a steady 700 RPM idle can extend engine life and reduce carbon buildup. It's recommended to check idle stability monthly, along with regular oil changes and maintenance. A simple test is to lightly press the accelerator to see if the response is quick; address any issues promptly to ensure safety and save on repair costs.